"""
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.
"""
def sumDivisibleBy(n,target=999):
    p = target / n
    return n*(p*(p+1))/2
def printResult():
    print (sumDivisibleBy(3) + sumDivisibleBy(5) - sumDivisibleBy(15))
printResult()



